Seal ring inductor and method of forming the same

ABSTRACT

Apparatuses and methods for providing inductance are disclosed. In one embodiment, a method for providing an inductor includes forming an electrical circuit on a substrate, forming a seal ring around the perimeter of the electrical circuit, providing a break in at least one layer of the seal ring, and electrically connecting the seal ring such that the seal ring operates as an inductor.

BACKGROUND

1. Field

Embodiments of the invention relate to electronics, and in particular,to inductors.

2. Description of the Related Technology

Radio frequency (RF) electronic systems such as receivers, transmittersand/or receivers can use an inductor for a variety of purposes. Forexample, a RF electronic system can include an inductor for protectingthe RF electronic system from an electrostatic discharge (ESD) event.Additionally, a RF electronic system can use an inductor for otherpurposes, such as for filtering a RF signal and/or for operating as achoke.

The inclusion of an inductor can increase the area and/or cost of anelectronic system. For example, a discrete inductor can be employed on aRF board of an electronic system, but the discrete inductor can increaseboard area and/or component count. Alternatively, an inductor can befabricated on an integrated circuit. However, an inductor fabricated onan integrated circuit can significantly increase chip area and/or cost.

There is a need for improved apparatus and methods for providinginductance.

SUMMARY

In certain embodiments, the present disclosure relates to an apparatusincluding a substrate, an electrical circuit disposed on the substrate,and a seal ring disposed on the substrate and surrounding the perimeterof the electrical circuit. The seal ring is configured to operate as aninductor and includes a first conductive layer configured to operate asa first coil of the inductor and having a first break defining a firstend and a second end of the first coil.

In some embodiments, the seal ring further includes a second conductivelayer adjacent the first conductive layer, the second conductive layerincluding a second break. In certain embodiments, the first break andthe second break at least partially overlap when the first and secondconductive layers are viewed from above the substrate.

According to a number of embodiments, the second conductive layer isconfigured to operate as a second coil of the inductor, the second breakdefining a first end and a second end of the second coil. In variousembodiments, the apparatus further includes a via for electricallyconnecting the second end of the first coil to the first end of thesecond coil.

According to some embodiments, the substrate is a gallium arsenide(GaAs) substrate.

In various embodiments, the inductor is configured to operate as achoke, the inductor including a first end electrically connected to abias circuit and a second end electrically connected to a radiofrequency circuit.

In a number of embodiments, the apparatus further includes a bonding paddisposed above the substrate and a pad protection circuit, the padprotection circuit including a first capacitor having a first endelectrically connected to the bonding pad and a second end electricallyconnected to a first end of the inductor.

In accordance with certain embodiments, the inductor includes a secondend electrically connected to a ground supply.

In various embodiments, the first end of the inductor and the second endof the capacitor are electrically connected to an antenna.

According to several embodiments, the first capacitor is disposed on thesubstrate and surrounded by the seal ring.

In some embodiments, the apparatus further includes a radio frequencyfilter and a first radio frequency circuit, the radio frequency filterincluding a first capacitor having a first end electrically connected tothe first radio frequency circuit and a second end electricallyconnected to a first end of the inductor. In accordance with variousembodiments, the apparatus includes a second capacitor having a firstend electrically connected to the second end of the capacitor and to thefirst end of the inductor. In some embodiments, the apparatus furtherincludes a second radio frequency circuit electrically connected to thesecond end of first capacitor and to the first end of the firstinductor.

In certain embodiments, the present disclosure relates to a method ofproviding an inductor. The method includes forming an electrical circuiton a substrate, forming a seal ring around the perimeter of theelectrical circuit, providing a break in at least one layer of the sealring, and electrically connecting the seal ring such that the seal ringoperates as an inductor.

In some embodiments, providing a break in at least one layer of the sealring includes providing a break in a conductive layer of the seal ringto form a coil of the inductor.

In certain embodiments, the method further includes providing a bondingpad above the substrate and electrically connecting the inductor so asto provide electrostatic discharge (ESD) protection to a circuitassociated with the bonding pad. In various embodiments, electricallyconnecting the inductor so as to provide ESD protection to the circuitassociated with the bonding pad includes providing a first capacitorhaving a first end electrically connected to the bonding pad and asecond end electrically connected to a first end of the inductor.

In various embodiments, the method further includes electricallyconnecting the first end of the inductor to an antenna.

According to a number of embodiments, the method further includeselectrically connecting a second of the inductor to a ground supply.

In certain embodiments, the method further includes electricallyconnecting the inductor such that the inductor operates as a radiofrequency filter.

In accordance with some embodiments, the method further includeselectrically connecting the inductor such that the inductor operates asa choke.

In certain embodiments, the present disclosure relates to an apparatusincludes a substrate means, an electronic circuit means disposed on thesubstrate means, and a seal ring means disposed on the substrate meansand surrounding the electronic circuit means. The seal ring means isconfigured to operate as an inductor and includes a first conductivelayer configured to operate as a first coil of the inductor. The firstconductive layer includes a first break defining a first end and asecond end of the first coil.

In some embodiments, the seal ring further includes a second conductivelayer adjacent the first conductive layer, the second conductive layerhaving a second break. In various embodiments, the second conductivelayer is configured to operate as a second coil of the inductor, thesecond break defining a first end and a second end of the second coil.According to a number of embodiments, the apparatus further includes avia for electrically connecting the second end of the first coil to thefirst end of the second coil.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view of a radio frequency (RF) integrated circuit (IC)according to one embodiment.

FIG. 1B is a cross-section of the RF IC of FIG. 1A taken along the line1B-1B.

FIG. 1C is a cross-section of the RF IC of FIG. 1A taken along the line1C-1C.

FIG. 1D is a cross-section of the RF IC of FIG. 1A taken along the line1D-1D.

FIG. 2A is a plan view of a RF IC according to another embodiment.

FIG. 2B is a cross-section of the RF IC of FIG. 2A taken along the line2B-2B.

FIG. 2C is a cross-section of the RF IC of FIG. 2A taken along the line2C-2C.

FIG. 2D is a cross-section of the RF IC of FIG. 2A taken along the line2D-2D.

FIG. 3A is a plan view of a RF IC according to yet another embodiment.

FIG. 3B is a cross-section of the RF IC of FIG. 3A taken along the line3B-3B.

FIG. 3C is a cross-section of the RF IC of FIG. 3A taken along the line3C-3C.

FIG. 3D is a cross-section of the RF IC of FIG. 3A taken along the line3D-3D.

FIG. 4 is a schematic block diagram of an electronic system according toone embodiment.

FIG. 5 is a schematic block diagram of an electronic system according toanother embodiment.

FIG. 6 is a schematic block diagram of an electronic system according toyet another embodiment.

FIG. 7A is a circuit diagram of a circuit in accordance with oneembodiment.

FIG. 7B is a circuit diagram of a circuit in accordance with anotherembodiment.

FIG. 7C is a circuit diagram of a circuit in accordance with yet anotherembodiment.

FIG. 8 illustrates a method for providing an inductor in accordance withone embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

Overview of Seal Ring Inductors

FIG. 1A is a plan view of a radio frequency (RF) integrated circuit (IC)10 according to one embodiment. The RF IC 10 includes a substrate 2, aseal ring 4, and circuit area 8.

The seal ring 4 can surround the perimeter of the circuit area 8 of theIC 10. The seal ring can be used for a variety of purposes, such as toprevent moisture from reaching the circuit area 8 and/or to aid inreducing the formation of cracks in the IC 10. For example, the IC 10can be fabricated on a wafer, and the seal ring 4 can aid in preventingthe formation of cracks in the IC 10 when the wafer is scribed and/ordiced to form a plurality of ICs.

The seal ring 4 can include a plurality of conductive, contact and/orvia layers, as will be described below. A break 6 can be included in oneor more conductive layers of the seal ring 4. The break 6 permits theseal ring 4 to be employed as an inductor in a circuit, as will bedescribed in detail herein.

Although the seal ring 4 is illustrated as having a rectangular shapewhen viewed from above the substrate, the seal ring 4 can have anysuitable shape, including, for example a square, oval or circle.

The substrate 2 can be any suitable substrate. In one embodiment, thesubstrate is a GaAs substrate. The substrate 2 can include a variety ofstructures, including, for example, one or more epitaxial layers to aidin fabricating transistors. The substrate 2 can be processed using anysuitable process.

The IC 10 can include the circuit area 8. The circuit area 8 can includea wide variety of transistors and/or other electronic structures,including, for example, pseudomorphic high electron mobility (pHEMT)transistors. As will be described in further detail below, the seal ring4 can be electrically connected to one or more circuit elements in thecircuit area 8 and/or to components externally located from the IC 10.For example, the IC 10 can be configured to operate as an inductor andelectrically connected to a capacitor fabricated in the circuit area 8and/or to a capacitor located external to the IC 10.

FIG. 1B is a cross-section of the RF IC of FIG. 1A taken along the line1B-1B. FIG. 1C is a cross-section of the RF IC of FIG. 1A taken alongthe line 1C-1C. FIG. 1D is a cross-section of the RF IC of FIG. 1A takenalong the line 1D-1D.

As illustrated in the cross-sections shown in FIGS. 1B-1D, the seal ring4 can include a plurality of conductive, contact and/or via layers. Forexample, the illustrated seal ring 4 includes a contact layer 13, afirst conductive layer 17, a first via layer 14, a second conductivelayer 18, a second via layer 15, and a third conductive layer 19.Persons having ordinary skill in the art will appreciate that a sealring can include more or fewer conductive layers, contact layers and/orvia layers. Additionally, the seal ring can include other layers inaddition to those illustrated, including, for example, well and/ordiffusion layers.

The first, second and third conductive layers 17-19 can be any suitableconductor, including for example, a metal comprising nickel (Ni),aluminum (Al), gold (Au), silver (Ag), tin (Sn), and/or aluminum (Al).The first, second and third layers 17-19 can have varying thicknesses,widths and/or compositions. Likewise, the contact layer 13 and first andsecond via layers 14, 15 can include a wide variety of materials, andcan include a metal such as those describing above with respect to theconductive layers 17-19.

The seal ring 4 includes the break 6. The break 6 permits the seal ring4 to operate electrically as an inductor. For example, providing thebreak 6 can result in a formation of a first end 7 a and a second end 7b of the seal ring 4, and the first and second ends 7 a, 7 b can beoperated as first and second ends of an inductor. The first end 7 a andthe second end 7 b of the inductor can be spaced by any suitabledistance, such as a distance d in the range of about 10 μm to about 20μm. The distance d can be selected to be the minimum spacing permittedby the processing technology.

By providing the break 6 in the seal ring 4, the seal ring 4 can operateas an inductor in an electrical circuit. Since the seal ring 4 cansurround the perimeter of the circuit area 8 of the IC 10, the seal ring4 can have a relatively large inductive coil and therefore a relativelylarge inductance. The seal ring 4 can be employed as an inductor in avariety of circuits, and can be used to reduce the area of an electronicsystem. For example, using the seal ring 4 as an inductor can reduce thearea of the IC 10 relative to a design that uses an inductor fabricatedin the circuit area 8. Additionally, using the seal ring 4 as aninductor can result in a reduction in area and/or cost of an electronicsystem relative to a system using a discrete inductor and/or an inductorformed using board trace.

FIG. 2A is a plan view of a RF IC 20 according to another embodiment.FIG. 2B is a cross-section of the RF IC of FIG. 2A taken along the line2B-2B. FIG. 2C is a cross-section of the RF IC of FIG. 2A taken alongthe line 2C-2C. FIG. 2D is a cross-section of the RF IC of FIG. 2A takenalong the line 2D-2D.

The RF IC 20 includes a substrate 2, a seal ring 24, and circuit area 8.The RF IC 20 can be similar to the RF IC 10 of FIGS. 1A-1D. However, incontrast to the seal ring 4 of the RF IC 10 of FIGS. 1A-1D, the sealring 24 of FIGS. 2A-2D is includes a plurality of inductive coils.

For example, as shown in FIG. 2C, the seal ring 24 can include a firstbreak 6 a in the first conductive layer 17, a second break 6 b in thesecond conductive layer 18, and a third break 6 c in the thirdconductive layer 19. The first break 6 a defines a first end 21 a and asecond end 21 b of the first conductive layer 17, the second break 6 bdefines a first end 22 a and a second end 22 b of the second conductivelayer 18, and the third break 6 c defines a first end 23 a and a secondend 23 b of the third conductive layer 19. By providing the first,second and third breaks 6 a-6 c, the first, second and third conductivelayers 17-19 can be configured to operate as coils of an inductor formedfrom the seal ring 24. The coils of the inductor can be electricallyconnected end-to-end using the first and second via layers 14, 15. Forexample, the first via layer 14 can be used to electrically connect thesecond end 21 b of the first conductive layer 17 to the first end 22 aof the second conductive layer 18, and the second via layer 15 can beused to connect the second end 22 b of the second conductive layer 18 tothe first end 23 a of the third conductive layer 19. Thus, the first end21 a of the first conductive layer 17 and the second end 23 b of thethird conductive layer 19 can operate as first and second ends of aninductor formed from the seal ring 24.

FIG. 3A is a plan view of a RF IC 30 according to another embodiment.FIG. 3B is a cross-section of the RF IC 30 of FIG. 3A taken along theline 313-313. FIG. 3C is a cross-section of the RF IC 30 of FIG. 3Ataken along the line 3C-3C. FIG. 3D is a cross-section of the RF IC 30of FIG. 3A taken along the line 3D-3D.

The RF IC 30 of FIGS. 3A-3D can be similar to the RF IC 10 of FIGS.1A-1D, and can include a break 6 in the first, second and thirdconductive layers 17-19. However, in contrast to the RF IC 10 of FIGS.1A-1D, the first, second and third conductive layers 17-19 of the RF IC30 of FIGS. 3A-3D are not interconnected in the seal ring 34 by thefirst and second vias 14, 15. Rather, the vias have not been included infavor of using the first, second, and third conductive layers asseparate inductive coils of the inductor. The coils of the inductor canbe electrically connected using vias in the circuit region 8 and/or byusing connections external to the RF IC 30. The inductive coils can beelectrically connected end-to-end to form an inductor, or used as coilsin different inductors.

FIG. 4 is an electronic system 40 according to one embodiment. Theelectronic system 40 includes an IC 41, an antenna 43, and anelectrostatic discharge (ESD) protection circuit 44. The IC 41 caninclude a plurality of pins or pads, including the pad 42. The pad 42can be configured to communicate with the antenna 43.

The antenna 43 can be exposed to an ESD event, such as the ESD event 45.The ESD protection circuit 44 can be electrically connected to the pad42 in order to protect the IC 41 from damage from the ESD event 45. Forexample, the ESD event can generate high voltage conditions, increasepower dissipation and heating, and/or induce latch-up when an ESDprotection circuit is not included to protect the IC 41.

The protection circuit 41 includes a capacitor 47 and an inductor 48.The capacitor 47 includes a first end electrically connected to the pad42, and a second end electrically connected to a first end of theinductor 48 and to the antenna 43. The inductor 48 further includes asecond end electrically connected to the voltage reference V₁, which canbe, for example, a ground node or a power supply.

During normal operation of the RF IC 41, the RF IC 41 can generate orreceive RF signals using the pad 42 that have a frequency greater thanthe frequency of signals associated with the ESD event 45. Thus, theprotection circuit 44 can include the capacitor 47 for passing highfrequency RF signals associated with typical operation of the RF IC 41.During an ESD event, the capacitor 47 can aid in providing ESDprotection by blocking a portion of the ESD event from reaching the RFIC 41. Additionally, the inductor 48 of the protection circuit 44 canshunt a portion of the charge associated with an ESD event 45 to thevoltage reference V₁ before it reaches the IC 41, thereby providing ESDprotection.

The RF IC 41 can include additional pins or pads that can beelectrically connected to other portions of the electronic system 40.The additional pins or pads can have one or more ESD protectioncircuits, such as the ESD protection circuit 44 of FIG. 4. Theadditional pins or pad need not be electrically connected to an antenna.

The inductor 48 can be formed using a seal ring of the IC 41. Forexample, any of the seal rings illustrated in FIGS. 1A-3D can be used toform the inductor 48 of the ESD protection circuit 44. By using a sealring of the IC 41 to function as an inductor, the area and/or cost ofthe electronic system can be reduced.

The capacitor 47 of the protection circuit 44 can be fabricated on theIC 41. For example, the capacitor 47 can be formed in the device area ofthe IC 41, in a manner similar to that illustrated by the device area 8shown in FIGS. 1A, 2A and 3A. Thus, the protection circuit 45 can befabricated entirely on the IC 41. However, all or a portion of thecapacitor 47 can be provided using components formed outside the IC 41,including, for example, by using a discrete component, such as a surfacemount component, to provide the desired capacitance. Thus, a portion ofthe protection circuit 44 can be external to the IC 41.

FIG. 5 is a schematic block diagram of an electronic system 50 accordingto another embodiment. The electronic system 50 includes a bias circuit51, a RF circuit 52 and a choke 53. The choke 53 includes a first endelectrically connected to the bias circuit 51 and a second endelectrically connected to the RF circuit 52.

The bias circuit 51 can be used to generate a reference current and/orvoltage for the RF circuit 52. The choke 53 can be used to aid inpreventing high-frequency components of the RF circuit 52 from reachingthe bias circuit 51, thereby enhancing the performance of the biascircuit 51.

The choke 53 can be provided by using a seal ring of an IC. For example,the choke 53 can be formed using the seal rings illustrated in FIGS.1A-3D. The IC used to form the choke 53 can be the same, or a differentIC as the IC of the RF circuit 52. For example, the bias circuit 51, theRF circuit 52 and the choke 53 can be provided on a single IC, and thechoke 53 can be formed from a seal ring of the IC. Alternatively, thebias circuit 51 can be provided on a first IC, the RF circuit 52 can beprovided on a second IC, and the choke 53 can be provided using the sealring of the first and/or second ICs.

FIG. 6 is a schematic block diagram of an electronic system 60 accordingto yet another embodiment. The electronic system 60 includes a first RFcircuit 52 a, a second RE circuit 52 b, and a RF filter 54. The RFfilter 54 includes a capacitor 57 and an inductor 58.

The capacitor 57 includes a first end electrically connected to thefirst RF circuit 52 a, and a second end electrically connected to thesecond RF circuit 52 b and to a first end of the inductor 57. Theinductor 58 further includes a second end electrically connected to thefirst and second RE circuits 52 a, 52 b. For example, the second end ofthe inductor 58 can be electrically connected to a ground node or anyother suitable node of the first and second RF circuits 52 a, 52 b.

The RF filter 54 can aid in filtering signals provided from the first RFcircuit 52 a to the second RF circuit 52 b and/or from the second RFcircuit 52 b to the first RF circuit 52 a. For example, the RF filter 54can be used as a high-pass filter for signals exchanged between thefirst and second RF circuits 52 a, 52 b.

The inductor 58 can be provided by using a seal ring of an IC. Forexample, the choke 53 can be formed using the seal rings illustrated inFIGS. 1A-3D. The first and second RF circuits 52 a, 52 b can be on asingle IC, and the inductor 58 can be formed from the seal ring of theIC. For implementations in which the first and second RF circuits 52 a,52 b are disposed on separate ICs, the seal ring used to form theinductor 58 can be on either or both of the ICs. The capacitor 57 can bea discrete component, can be integrated onto one or more ICs, and/or caninclude both integrated and discrete components.

The RF filter 54 illustrates one example of a filtering circuit using aninductor. Persons having ordinary skill in the art will appreciate thata wide variety of other filter circuits including an inductor can beused in accordance with the seal ring inductors described herein.

FIG. 7A is a circuit diagram of a circuit 70 in accordance with oneembodiment. The circuit 70 includes a first inductor 64, a secondinductor 65, a third inductor 66, and a capacitor 67.

The first inductor 64 includes a first end electrically connected to anode N₁, and a second end electrically connected to a first end of thesecond inductor 65 and to a first end of the capacitor 67. The secondinductor 65 further includes a second end electrically connected to thereference voltage V₁. The capacitor 67 further includes a second endelectrically connected to a first end of the third inductor 66 and tothe second node N₂. The second inductor 66 further includes a second endelectrically connected to the reference voltage V₁.

The first, second and/or third inductors 64-66 can be fabricated using aseal ring of an IC, such as the seal rings illustrated in FIGS. 1A-3D.For example, the first, second and third conductive layers of FIGS.3A-3D can operate as the first, second and third inductors 64-66,respectively. The first, second and third inductors can also be providedusing a combination of IC seal rings and/or discrete components,including, for example, inductors formed from board trace. The capacitor67 can be a capacitor formed on an IC, or can be a discrete component,such as a surface mount device disposed on a RF circuit board.

The circuit 70 of FIG. 7A can be used in a wide variety of electronicsystems. For example, the node N₁ can be electrically connected to a pinor pad of an IC and the node N₂ can be electrically connected to anantenna or other part of an electronic system to provide ESD protection.The circuit 70 can also be used in other applications, including, forexample, as a RF filter. For example, the node N₁ can be electricallyconnected to a first RF circuit and the node N₂ can be electricallyconnected to a second RF circuit, and the circuit 70 can be used tofilter signals communicated between the first and second RF circuits.Persons of ordinary skill in the art will appreciate that the circuit 70of FIG. 7A can be used in additional applications.

FIG. 7B is a circuit diagram of a circuit 80 in accordance with anotherembodiment. The circuit 80 includes a first inductor 77, a secondinductor 78, a first capacitor 74, and a second capacitor 75.

The first capacitor 74 includes a first end electrically connected to anode N₁, and a second end electrically connected to a first end of thefirst inductor 77 and to a first end of the second capacitor 75. Thefirst inductor 77 further includes a second end electrically connectedto the reference voltage V₁. The second capacitor 75 further includes asecond end electrically connected to a first end of the second inductor78 and to the second node N₂. The second inductor 78 further includes asecond end electrically connected to the reference voltage V₁.

The first and/or second inductors 77, 78 can be fabricated using a sealring of an IC, including, for example, the seal rings illustrated inFIGS. 1A-3D. The first and second inductors can also be provided using acombination of one or more IC seal rings and discrete components,including, for example, inductors formed from board trace and/orprovided as surface mount components. The first and second capacitors74, 75 can be provided using any suitable combination of integratedand/or discrete components.

The circuit 80 of FIG. 7B can be used in a wide variety ofconfigurations in an electronic system. For example, the circuit 80 canbe used as an ESD protection circuit for a RF IC, as a RF filter in anelectronic system, and/or in any other suitable application.

FIG. 7C is a circuit diagram of a circuit 90 in accordance with yetanother embodiment. The circuit 90 includes a first inductor 85, asecond inductor 86, and a capacitor 87.

The capacitor 87 includes a first end electrically connected to a nodeN₁ and to a first end of the first inductor 85, and a second endelectrically connected to the second node N₂ and to a first end of thesecond inductor 86. The first inductor 85 further includes a second endelectrically connected to the reference voltage V₁. The second inductor86 further includes a second end electrically connected to the referencevoltage V₁.

The first and/or second inductors 85, 86 can be fabricated using a sealring of an IC, as was described earlier. The first and second inductorscan also be provided using one or more IC seal rings in combination withother elements, including, for example, discrete or integrated inductivecomponents. The capacitor 87 can be provided in any suitable manner, aswas described earlier.

The circuit 90 of FIG. 7C can be used in a wide variety ofconfigurations in an electronic system. For example, circuit 90 can beemployed as an ESD protection circuit, as a RF filter in an electronicsystem, and/or in any other suitable application.

FIG. 8 illustrates a method 100 for providing an inductor in accordancewith one embodiment. It will be understood that the methods discussedherein may include greater or fewer operations and the operations may beperformed in any order, as necessary. The illustrated method can be usedto provide, for example, the inductive seal ring structures of FIGS.1A-3D.

The method 100 for providing an inductor starts at 101. In an ensuingblock 102, an electrical circuit is formed on a substrate. Theelectrical circuit can be formed in a circuit area of the substrate, aswas described above with reference to FIG. 1A. The electrical circuitcan include transistors, capacitors, resistors, inductors, and/or anyother suitable component, and can provide RF functionality. For example,the electrical circuit can be configured to generate signals for use byan antenna.

The method 100 continues at a block 104, in which a seal ring is formedaround the perimeter of the electrical circuit. The seal ring includes abreak in at least one layer of the seal ring. When viewed from above,the seal ring can have any suitable shape, including, for example asquare, rectangle, oval or circle that surrounds the perimeter of theelectrical circuit formed in block 102. The seal ring can preventmoisture from reaching the electrical circuit and/or can prevent theformation of cracks in the substrate, which can propagate into theportion of the substrate used to form the electrical circuit, therebyrendering the electrical circuit inoperable.

In an ensuing block 106, the seal ring is electrically connected tooperate as an inductor. For example, the break in the seal ring formedin block 104 can result in the seal ring having a first end and a secondend that can be operated as first and second ends of an inductor. Thus,the first end of the seal ring can be electrically connected to a firstnode of an electronic system, and the second end of the seal ring can beelectrically connected to a second node of the electronic system, andthe seal ring can operate as an inductor in the electronic system. Incertain implementations, the seal ring operates as an inductor in theelectrical circuit formed in block 102. However, in otherimplementations, the seal ring operates as an inductor in a circuit thatis at least partially external to the substrate the seal ring isdisposed on. Since the seal ring surrounds the perimeter of theelectrical circuit formed in block 102, the seal ring can be relativelylarge and can have a relatively large inductance. The seal ring can beelectrically connected and configured to operate as an inductor in awide variety of electrical systems, including RF filter systems, ESDprotection systems, and/or biasing systems.

Applications

The seal ring inductors described herein can be implemented in variouselectronic devices. Examples of the electronic devices can include, butare not limited to, consumer electronic products, parts of the consumerelectronic products, electronic test equipment, etc. Examples of theelectronic devices can also include, but are not limited to, memorychips, memory modules, circuits of optical networks or othercommunication networks, and disk driver circuits. The consumerelectronic products can include, but are not limited to, a mobile phone,a telephone, a television, a computer monitor, a computer, a hand-heldcomputer, a personal digital assistant (PDA), a microwave, arefrigerator, an automobile, a stereo system, a cassette recorder orplayer, a DVD player, a CD player, a VCR, an MP3 player, a radio, acamcorder, a camera, a digital camera, a portable memory chip, a washer,a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, amulti functional peripheral device, a wrist watch, a clock, etc.Further, the electronic devices can include unfinished products.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “can,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

1. An apparatus comprising: a substrate; an electrical circuit disposedon the substrate; and a seal ring disposed on the substrate andsurrounding the perimeter of the electrical circuit, the seal ringconfigured to operate as an inductor, the seal ring including a firstconductive layer configured to operate as a first coil of the inductorand having a first break defining a first end and a second end of thefirst coil.
 2. The apparatus of claim 1 wherein the seal ring furtherincludes a second conductive layer adjacent the first conductive layer,the second conductive layer including a second break.
 3. The apparatusof claim 2 wherein the second conductive layer is configured to operateas a second coil of the inductor, the second break defining a first endand a second end of the second coil.
 4. The apparatus of claim 3 furthercomprising a via for electrically connecting the second end of the firstcoil to the first end of the second coil.
 5. The apparatus of claim 2wherein the first break and the second break at least partially overlapwhen the first and second conductive layers are viewed from above thesubstrate.
 6. The apparatus of claim 1 wherein the substrate is agallium arsenide (GaAs) substrate.
 7. The apparatus of claim 1 whereinthe inductor is configured to operate as a choke, the inductor includinga first end electrically connected to a bias circuit and a second endelectrically connected to a radio frequency circuit.
 8. The apparatus ofclaim 1 further comprising a bonding pad disposed above the substrateand a pad protection circuit, the pad protection circuit including afirst capacitor having a first end electrically connected to the bondingpad and a second end electrically connected to a first end of theinductor.
 9. The apparatus of claim 8 wherein the inductor includes asecond end electrically connected to a ground supply.
 10. The apparatusof claim 8 wherein the first end of the inductor and the second end ofthe capacitor are electrically connected to an antenna.
 11. Theapparatus of claim 8 wherein the first capacitor is disposed on thesubstrate and surrounded by the seal ring.
 12. The apparatus of claim 1further comprising a radio frequency filter and a first radio frequencycircuit, the radio frequency filter including a first capacitor having afirst end electrically connected to the first radio frequency circuitand a second end electrically connected to a first end of the inductor.13. The apparatus of claim 12 further comprising a second capacitorhaving a first end electrically connected to the second end of thecapacitor and to the first end of the inductor.
 14. The apparatus ofclaim 12 further comprising a second radio frequency circuitelectrically connected to the second end of first capacitor and to thefirst end of the first inductor.
 15. A method of providing an inductor,the method comprising: forming an electrical circuit on a substrate;forming a seal ring around the perimeter of the electrical circuit;providing a break in at least one layer of the seal ring; andelectrically connecting the seal ring such that the seal ring operatesas an inductor.
 16. The method of claim 15 wherein providing a break inat least one layer of the seal ring includes providing a break in aconductive layer of the seal ring to form a coil of the inductor. 17.The method of claim 15 further comprising providing a bonding pad abovethe substrate and electrically connecting the inductor so as to provideelectrostatic discharge (ESD) protection to a circuit associated withthe bonding pad.
 18. The method of claim 17 wherein electricallyconnecting the inductor so as to provide ESD protection to the circuitassociated with the bonding pad includes providing a first capacitorhaving a first end electrically connected to the bonding pad and asecond end electrically connected to a first end of the inductor. 19.The method of claim 18 further comprising electrically connecting thefirst end of the inductor to an antenna.
 20. The method of claim 19further comprising electrically connecting a second of the inductor to aground supply.
 21. The method of claim 15 further comprisingelectrically connecting the inductor such that the inductor operates asa radio frequency filter.
 22. The method of claim 15 further comprisingelectrically connecting the inductor such that the inductor operates asa choke.
 23. An apparatus comprising: a substrate means; an electroniccircuit means disposed on the substrate means; and a seal ring meansdisposed on the substrate means and surrounding the electronic circuitmeans, the seal ring means configured to operate as an inductor, theseal ring means including a first conductive layer configured to operateas a first coil of the inductor, the first conductive layer having afirst break defining a first end and a second end of the first coil. 24.The apparatus of claim 23 wherein the seal ring further includes asecond conductive layer adjacent the first conductive layer, the secondconductive layer having a second break.
 25. The apparatus of claim 24wherein the second conductive layer is configured to operate as a secondcoil of the inductor, the second break defining a first end and a secondend of the second coil.
 26. The apparatus of claim 25 further comprisinga via for electrically connecting the second end of the first coil tothe first end of the second coil.